Horsepower! - 740hp, 540ci Dodge

We happened to be at IMM Engine & Dyno the day owner Brian Hafliger was testing this 540ci 440 stroker. He built it for a customer who will be dropping it into a 1967 Barracuda and competing in Hot Rod's Drag Week this summer. We like it for its simple, effective combination of parts and for the fact that it was built to make max power yet still offer good driveability on pump gas. Meeting all those criteria aren't as easy as you'd think. Let's see how Brian fared.

1. Block

Brian started with a new engine block from Mopar Performance with a finished bore size of 4.500-inch. The rotating assembly consists of a 4.250-inch stroke Scat lightweight crankshaft, Scat connecting rods, and Diamond pistons.

2. Fuel

That's one of Holley's new Gen3 Dominator carburetors. Brian chose it based on past experience with testing engines at this displacement on his dyno. He told us Dominator carburetors always seem to make a bit more power than a 4150-style carburetor. "I find they are pretty good right out of the box. If I need to make any changes, it's usually just two jet sizes off," he says.

3. Exhaust

The TTi headers installed here on the dyno are the same headers the customer will be using on this engine when it's in the car. They have 2-inch primary tubes and 31⁄2-inch collectors. "Anything bigger will require oval tubing to fit under the car, and that would be really expensive," Brian says.

4. Cam

The camshaft is a custom grind spec'd by Brian. It's a solid roller measuring 267/273 degrees duration and 0.700-inch valve lift. A set of T&D shaft-mount rocker arms actuates the valves. Brian chose to use 1.7:1 ratio on the intake and 1.6:1 on the exhaust.

5. Heads

Indy's new EZ-325 CNC-ported cylinder heads flow more than 350 cfm of air at 0.600-inch lift on the intake side, and mid-lift flow is just as impressive. Credit goes to the efficient intake runner design, and full CNC-porting of the combustion chamber and intake and exhaust runners. The valve sizes are 2.25-/1.81-inch, and the combustion chamber size is 82 cc, making the compression ratio a pump-gas friendly 10.4:1.

IMM Engines & Dyno is a family-owned business that has operated out of the same location on Flower Street in Indio, California, since 1955. Brian's great grandfather founded the business, his father began working there in his early 20s, and Brian began working there in high school. It's almost always been a two-man shop. Brian has a reputation as a Mopar specialist, but they work on anything there, from tractor engines and farm implements to diesel engines and motorcycles. Check them out at IMMEngines.com.